Integrated optimization of water-land resource allocation and cropping structure in large irrigation districts
CHEN Siyuan
CHENG Zhiyuan
ZHOU Ting
WANG Dongxia
ZHU Feilin
ZHANG Qibing
JIAO Pingjin
Abstract：[Objective]Irrigation districts are essential for food security,and efficient allocation of water and land resources is fundamental to their sustainable production.A major challenge in many irrigation districts is the mismatch between agricultural water demand and natural water availability.This paper developed an optimization model by coupling water-land resource allocation with cropping structure adjustment to alleviate this mismatch.[Method]The proposed model minimizes total irrigation water shortage during the irrigation period by treating crop planting areas and grouped reservoir operation as the decision variables to coordinate regulation of both water supply and demand.The model was applied to the Pishihang Irrigation District in China to optimize water allocation from six reservoirs by adjusting rice cropping structure.[Result]Under the 80%design reliability scenario,the optimized scheme reduced the annual total water shortage by 94 million m3 compared with the conventional allocation scheme,while increasing the rice planting area by 20.1 thousand hectares.Under the consecutive dry-year scenario(2000-2001),the adjusted cropping structure,combined with inter-annual reservoir operation and full utilization of multi-year storage capacity,ensured water supply during critical crop growth stages.This increased the rice planting area from 74.0 thousand hectares in 2000 to 226.6 thousand hectares in 2001,significantly enhancing drought resilience and water supply reliability.Under a water-saving irrigation scenario,a 9%-10%reduction in irrigation quota resulted in a 9.7%-10.8%increase in rice planting area without increasing total water shortage.[Conclusion]The proposed model coordinated the optimization of spatiotemporal water resource allocation and cropping structure;it provides a quantitative decision-support tool for implementing the'Four Water Determinations'principle and promotes the sustainable and efficient use of water and land resources in irrigation districts.
Keywords：water and land resources optimizationcropping structurereservoir operationfour water determinationsPishihang irrigation district
Publication Date：2026-06-30
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：10( 120-129 )